The present invention relates to an image photographing apparatus and, more particularly, to an image photographing apparatus for digitizing interleaved data from an image sensing section by an A/D conversion section and storing the data.
In a conventional image photographing apparatus of this type called an electronic camera, interleaved data extracted as an analog value from an image sensing section having an image sensing element such as a CCD is converted into a digital value by an A/D conversion section and stored in a nonvolatile digital memory device such as a nonvolatile digital semiconductor memory device, solid-state memory device, or floppy disk memory device.
FIG. 7 shows a conventional image photographing apparatus. FIG. 8 shows the operations of various portions of the conventional image photographing apparatus.
Upon detecting the ON state of the shutter button (not shown) of an operation section 6 at time T1, a control section 5 outputs an image receiving instruction to an image sensing section 1.
In response to this, the image sensing section 1 photoelectrically converts an image sensed through an optical system 2 and outputs interleaved data (image sensing output data) comprised of a number of discrete analog values representing pieces of color information of pixels in synchronism with a predetermined clock signal.
This interleaved data is converted into a digital value by an A/D conversion section 3 from time T2, developed into image data and compressed by an image signal processing section 4 such as a DSP, and then stored in a nonvolatile digital memory device 7 (digital memory device) from T3.
Compression is processing of reducing the amount of resultant image data. By compression, the amount of data stored in the nonvolatile digital memory device 7 is decreased to make it possible to store more image data.
When a display section 8 such as an LCD is provided, as needed, the image data from the image sensing section 1 or image signal processing section 4 is displayed on a screen of the display section 8.
In the conventional image photographing apparatus, however, interleaved data obtained from the image sensing section is A/D-converted and compressed, and then stored in the nonvolatile digital memory device. For this reason, a new image cannot be received while these operations are being performed. That is, images cannot be continuously received at a short interval.
When an A/D conversion section 3 or image signal processing section 4 having high processing performance is used, the processing time can be shortened to some extent. However, such a high-performance A/D converter or DSP is expensive to result in an increase in cost of the product.
The present invention has been made to solve the above problem, and has as its object to provide an image photographing apparatus capable of continuously receiving images at a short interval.
In order to achieve the above object of the present invention, there is provided an image photographing apparatus for storing interleaved data having a number of discrete analog values which is output from an image sensing section and digitized by an A/D conversion section, comprising an analog semiconductor memory device for storing the interleaved data from the image sensing section as analog data, and a control section for writing the interleaved data output from the image sensing section upon photographing in the analog semiconductor memory device, reading out the written interleaved data from the analog semiconductor memory device, and outputting the data to the A/D conversion section.